Electric vehicles

Abstract

A battery vehicle having a normal speed range for house to house deliveries and an extended speed range for lengthy journeys such as to and from delivery rounds. The extended speed range is engageable by operation of a manual range control. The manual range control is rendered inoperative on startup so that the extended speed range is not immediately available. After a delay, of predetermined period, or after a delay of predetermined period during which the speed has been held at, or above, a determined limit, or after the vehicle has covered a predetermined distance, the manual range change is enabled.

The embodiments of the invention in which an exclusive property or right is claimed are defined as follows: 
     
       1. An electric battery powered vehicle comprising: a start/variable speed controller;   manual speed range means for changing the speed range capability of the vehicle by at least one step;   an electric drive motor responsive to the setting of said start/variable speed controller and said manual speed range means to provide the desired speed of operation;   said manual speed range means including a settable manual operation and control means responsive to the setting of said manual operator for expanding the range of drive voltages applied to said drive motor by said at least one step;   wherein said control means includes delay means operative to temporarily render said control means non-responsive to the actuation of said operator upon startup of the vehicle so as to prevent the upper fraction of the speed range being available to the driver during short journeys such as occur with house to house deliveries.   
     
     
       2. A vehicle according to claim 1 wherein said control means further comprises displacement transducer means connected to the said delay means for providing a signal thereto when the vehicle has traversed a predetermined distance from its startup position, said delay means being responsive to said signal to enable said control means to respond to actuation of the manual operator. 
     
     
       3. A vehicle according to claim 1 wherein said delay means comprises a timer operatively coupled to the said start/variable speed controller so as to having a timing cycle initiated when the said controller is moved from a non-driving to a driving position. 
     
     
       4. In an electric vehicle, traction means comprising: a. a battery-operated drive motor;   b. first and second batteries;   c. switching means for connecting the first and second batteries each in parallel with the motor in a first state of the switch means and for connecting the first and second batteries each in series with the motor in a second state thereof;   d. a start/variable speed controller in series with said batteries and said motor;   e. control means having a manual operator and including means for operating the said switching means; and   f. delay means connected to the said control means for temporarily disabling the said control means upon startup of the vehicle so as to delay the operation of the switching means and thus prevent the upper fraction of the speed range being available to the driver during short journeys such as occur with house to house deliveries.   
     
     
       5. Traction means according to claim 4 further comprising displacement transducer means coupled to the said drive motor and connected to the said delay means for providing a signal thereto when the said vehicle has traversed a predetermined distance from startup. 
     
     
       6. Traction means according to claim 4 wherein said delay means comprises a timer which is coupled to the said start/variable speed controller so as to have a timing cycle initiated when the said controller is moved from a non-driving to a driving position. 
     
     
       7. Traction means according to claim 4 wherein the said two batteries are connected in series via a first normally open switch which is initially locked out by said control means and are connected in parallel through a pair of normally closed switches which are open circuited when the said first switch is closed. 
     
     
       8. Traction means according to claim 4 wherein the said two batteries are connected in series via a first normally open switch which is initially locked out by the said control means, and the batteries are connected in parallel via rectifiers which are back-biassed when the said first switch is closed. 
     
     
       9. In an electric battery powered vehicle having a start/variable speed controller and a manual speed range facility for changing the speed range capability of the vehicle by at least one step, a solid state controller comprising: a. a pulse rate generator, having a first input connected to the variable speed controller;   b. a thyristor chopper which receives pulses from the pulse rate generator and delivers pulses of direct current to the vehicle drive at a rate dependent upon the pulse rate of the said pulse rate generator;   c. a manual operator for selecting a wider speed range;   d. velocity feedback means connected via a feedback loop to a second input of the said pulse rate generator for limiting the rate at which current pulses are supplied thereby so that the speed of the vehicle corresponds with the setting of the variable speed controller; and   e. delay means which, after a short period of operation of the vehicle from startup, and upon operation of the said manual operator, disconnects the velocity feedback from the solid state controller.   
     
     
       10. A solid state controller according to claim 9 wherein the delay means comprises timing means. 
     
     
       11. A solid state controller according to claim 10 further comprising a first level detector which has a first input connected to receive a reference signal from a first reference potential source, a second input connected to receive the velocity feedback signal and an output connected to the said timing means to provide an enabling signal thereto initiating a timing cycle when the magnitude of the velocity feedback signal exceeds the value of the reference signal, the said timing means providing a disabling output signal at the end of its timing cycle which disconnects the velocity feedback signal from the pulse rate generator. 
     
     
       12. A solid state controller according to claim 11 comprising a memory means, a first gate having a first input provided by the said manual operator when the latter is actuauted and an output connected to an input of the memory means, a controlled switch having a main conductive path which is connected in series with the said feedback loop and a control input connected to the output of the memory means, said switch being held in its conductive condition by an enabling signal provided by the memory means when the latter is in a first state, said timing means having an output connected to the second input of said first gate and providing an enabling signal thereto at the end of its period which, subject to the provision of a signal from the said manual operator, causes the memory means to change to a second state in which it provides a disabling signal to the control input of the said controlled switch, thereby rendering the latter non-conductive. 
     
     
       13. A solid state controller according to claim 12 further comprising an indicating lamp and a second gate having an output connected to the said indicating lamp, a first input connected to the output of the said timing means and a second input connected to the output of the said memory means, said second gate being enabled when the timing means reaches the end of its period and the said memory means is in its first state, thereby energising the said indicating lamp. 
     
     
       14. A solid state controller according to claim 12 wherein the said memory means has a second input which is connected to the output of the said first level detector via a third gate connected in series with an inverter and wherein the signal provided at the said second input when the velocity feedback signal falls below the value of the reference signal causes the memory means to assume its first state. 
     
     
       15. A solid state controller according to claim 14 wherein said timing means is adapted to reset whenever the output of the said level detector corresponds to a condition in which the velocity feedback signal is less than the said reference signal. 
     
     
       16. A solid state controller according to claim 14 wherein the third gate has a conditioning input which is connected to the vehicle start controller. 
     
     
       17. A solid state controller according to calim 14 wherein the memory means comprises a flip-flop which in its reset state provides a high level signal to the control input of the said controlled switch to cause the latter to be conductive and in its set state provides a low level signal to the said controlled switch causing the controlled switch to be non-conductive. 
     
     
       18. A solid state controller according to claim 12 further comprising a threshold amplifier connected in the negative feedback loop in series with the controlled switch, said threshold amplifier having a first input connected to the velocity feedback means and a second input connected to receive a reference signal from a second reference potential source, said reference signal being higher in value than the signal provided by the first reference potential source. 
     
     
       19. A solid state controller according to claim 18 wherein the said threshold amplifier has a non-linear transfer characteristic, there being a smaller change of the output thereof for changes in low level input signals as compared with the change produced at the output for changes in high level input signals. 
     
     
       20. A solid state controller according to claim 18 further comprising warning means and a second level detector having a first input connected to receive the velocity feedback signal and a second input connected to receive a reference signal derived from a third reference potential source, the said reference signal being of higher magnitude than the reference signal provided at the second input of the said threshold amplifier and an output connected to the said warning means whereby an alarm signal is provided when the speed of the vehicle rises above a predetermined maximum. 
     
     
       21. A solid state controller according to claim 9 wherein said velocity feedback means comprises an apertured disc coupled to the drive motor of the vehicle for rotation therewith, a magnetic perception head arrannged in a functional relationship with the said apertured disc and a frequency-to-analog converter which is coupled to receive the signal provided by the magnetic perception head and provide an analog output signal representative of the speed of the motor. 
     
     
       22. An electric vehicle according to claim 12 wherein said timer has a reset input and further comprising resetting signal generating means responsive to the operation of the said manual operator before the expiry of said timing cycle for providing a reset input to said timer thereby causing a restarting of the timing cycle. 
     
     
       23. An electric vehicle according to claim 22 wherein said resetting signal generating means comprises a one-shot device having its output connected to the reset input of the timer and having an input connected to energising contacts which are operated by said manual operator, said one-shot device delaying the resetting of the timer with respect to the operation of said manual operator so that when engaging the second mode of operation following the completion of a timing cycle the memory is placed into its said second state before the said timer resets in response to the said reset input.